JPS58219231A - Alkyd resin for coating material - Google Patents

Abstract

PURPOSE:The titled resin, containing an alicyclic and aromatic carboxylic acid components and an inorganic or organic phosphorus compound in specific amounts in an alkyd resin, and capable of giving coating films having improved weathering resistance, pigment dispersibility and waxing resistance. CONSTITUTION:An alkyd resin for coating materials, prepared by condensing (A) a mixture of an alicyclic carboxylic acid, e.g. 1,3-cyclohexanedicarboxylic acid, with an aromatic carboxylic acid, e.g. terephthalic acid, at (50:50)-(95:5) molar ratio with (B) an alcoholic component, e.g. ethylene glycol, and (C) an inorganic phosphorus compound, e.g. phosphoric acid, or an organic phosphorus compound, e.g. trimethyl phosphate, and adding a pigment to the resultant condensate. The amounts of the components (A) and (C) based on the the total resin are as follows: 30wt% or more component (A) and 0.1-5wt% component (C). The oil length is 50% or less, and the number-average molecular weight is 1,000-6,000.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new and useful alkyd resin for coatings, and more particularly, it relates to a new and useful alkyd resin for coatings, and more particularly, it relates to an automotive top coating using a specific carboxylic acid component and condensing a specific amount of an inorganic or organic phosphorus compound. Regarding resin for paint.

In recent years, there has been a strong desire for paints with excellent weather resistance to save resources, and this demand is particularly strong in the automobile industry. Paints that have a glossy appearance and have a coating film that does not fade due to waxing even when waxed have appeared, and this has become a goal set in the paint industry.

Conventionally, resins for top coatings on automobiles have mainly been acrylic resins combined with melamine/formaldehyde resins for metallic coatings, and coconut oil-modified or synthetic fatty acid-modified short oils for solid color coatings. Alkyd resins have been used in combination with similar melamine resins.

However, none of these resins has a high degree of weather resistance, which is a fatal defect especially when used in top coatings for automobiles.

However, as a result of intensive research by the present inventors in order to eliminate all of the drawbacks of conventional resins as described above and to obtain a resin that has a high degree of weather resistance and also has excellent gloss and hardenability, We have previously filed an application for a paint resin composition that is a blend of specific alkyd resins as disclosed in Japanese Patent No. 36149, but we are conducting further research and applying it specifically to organic pigments for automobile solid colors. The present invention was completed by discovering a resin with excellent dispersibility.

That is, the present invention provides an inorganic or Organophosphorus compounds are present in the total resin at 0.
1 to 5% condensed by weight, an oil length of 50% or less, and
The present invention provides an alkyd resin for paints having a number average molecular weight of 1,000 to 6,000.

As described in the earlier Japanese Patent Application Laid-open No. 57-36149, the present inventors started by obtaining a resin with high gloss retention through outdoor haze and accelerated weathering tests. Excellent adsorption power to inorganic pigments such as type titanium oxide, or organic pigments such as quinacridone or threnic red pigments, anthathurone orange pigments, or quinophthalone yellow pigments, as well as prevention of paint film deterioration. These pigments are protected from UV rays, heat, WLS, moisture, etc., which are factors that accelerate the process, and the resin itself does not deteriorate as described above.

It was concluded that the resin for solid colors of this type must be resistant to energy in order to improve its weather resistance.

Incidentally, although the surface of the above-mentioned titanium oxide is covered with hydroxyl groups, once such a pigment comes into contact with ultraviolet rays, oxygen, or moisture, which are the above-mentioned deterioration accelerating factors, or is kept in such an atmosphere, The deterioration energy generates radicals that cause deterioration of the matl itself, and also has the effect of accelerating this deterioration. As a measure to prevent the collapse of the resin itself due to the deterioration mechanism, we have discovered that adsorbing a resin condensed with an inorganic or organic phosphorus compound onto pigments is an effective and retroactive measure. , that is, the molar ratio of alicyclic carboxylic acid and aromatic carboxylic acid is 50:50 to 95
0.1 to 5% by weight, preferably 0.25 to 2% by weight of an organic phosphorus compound in an alkyd resin obtained by using both carboxylic acids as essential acid components. It has also been revealed that by condensing within a range of % by weight, a resin meeting the above-mentioned purpose can be obtained.

The amount of condensed inorganic or organic phosphorus compound is O, 1% by weight
If it is less than 5%, the adsorption power of the resin to the pigment will be weak and the object of the present invention will not be achieved.On the other hand, if it exceeds 5%, the adsorption power will be too strong and the paint system will become unstable. Both of these are undesirable, since they have a viscous nature and the resin itself is susceptible to hydrolysis.

The molar ratio of alicyclic carboxylic acid and aromatic carboxylic acid is 50
: If the amount of alicyclic carboxylic acid exceeds 50 and the amount of alicyclic carboxylic acid becomes too small, sufficient weather resistance cannot be exhibited;
If the amount of aromatic carboxylic acid is too small by increasing the ratio to more than 5, sufficient gloss and sharpness cannot be achieved, which is not preferable.

The organic phosphorus compound referred to in the present invention refers to all compounds except phosphinic acid, and the most representative ones are as follows.

For example, a dialkyl phosphate or trialkyl phosphate compound represented by the general formula, or a general formula (wherein R is as described above). The dialkyl phosphite compounds represented by ] are effective, and trinotyl phosphate, triethyl phosphate, triphenyl phosphate, di-n-butyl phosphate or [Super Beckamine P-198J (01- Phosphate ester of Cs alcohol); dimethyl phosphite, dimethyl phosphite or [Aditol XL-180J (organophosphorus compound manufactured by Hoechst, West Germany), etc. are useful.

5- In addition, typical inorganic phosphorus compounds include phosphoric acid, phosphorous acid, phosphorus pentoxide, and tripolyphosphoric acid,
From an operational point of view, it is desirable to use the above-mentioned organic phosphorus compounds.

As a method for condensing such an inorganic or organic phosphorus compound into a resin, in the fatty acid method, it is preferable to introduce the compound from the early stage of the reaction, and in the case of oil washing, it is preferable to introduce the compound immediately after the completion of the alcohol exchange reaction to cause the esterification reaction. However, this does not preclude addition in the latter half of the condensation reaction of the alkyd resin.

Incidentally, the preferred oil length for the resin of the present invention is 50% or less, particularly preferably 5 to 40%. If it exceeds 50%, not only the film hardness of the resulting paint becomes low, but also the pigment dispersibility becomes significantly poor.

On the other hand, the molecular weight of the resin of the present invention is also an important factor,
The number average molecular weight referred to in the present invention is calculated by the following formula, however, only the organic phosphorus compound is not included in this calculation.

M n =W/ (K - P)e4
(rV) This calculation formula is published by Interscience Publishers 6-Divisions of Chiron Wiley & Sons.
rs divisions of John Wile
T.C. Paraton (T.C.) published by yand 5ons>.

``Alkyd Resin Technology'' by Patton)
This is published as Formula 18 on page 110 of ``Y'').

If the molecular weight calculated in this way is less than 1000, the hardness and chemical resistance of the coating film will be poor, while if it exceeds 6000, wetting to the pigment will be poor, and the protective effect of the pigment will be weakened. Both are unfavorable because the molecular weight becomes too high, which impairs spray workability and ultimately impractical.

Here, to explain the alkyd resin in detail, first, typical examples of the alicyclic carboxylic acids that form the main component of the core component include 1.1-cyclohexanedicarboxylic acid, hexahydrophthalic acid, 1. Examples include 3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and methylhexahydrophthalic acid, and in addition, 4-tajaribdelcyclohexanemonocarboxylic acid and hexahydrobenzoic acid, as required. Cyclohexane monocarboxylic acids, cyclohexane polycarboxylic acids, and even their methyl esters can be used similarly.

On the other hand, typical aromatic carboxylic acids include (
(anhydrous) phthalic acid, isophthalic acid, or terephthalic acid, and if necessary, monocarboxylic acids such as benzoic acid, p-terciselygutylbenzoic acid, or p-methylbenzoic acid are also effective as molecular weight modifiers. Additionally, polycarboxylic acids such as trimellitic anhydride or pyromellitic anhydride can be used with various acid components as described above.

Furthermore, in addition to the acids described above, the alkyd resin of the present invention includes adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, hetonic anhydride, hymic anhydride, maleic anhydride, and fumaric anhydride. Acids such as itaconic acid or methylcyclohexenetricarboxylic anhydride can be used.

There are no particular restrictions on the alcohol component used with the above acid components, but representative ones include ethylene glycol, propylene glycol, 1.
3-butylene glycol, 1,6-hexanediol,
Examples include diethylene glycol, triethylene glycol, neopendel glycol, triethylene glycol, cyclohexane dimetatool, hydrogenated bisphenol A1 glycerin, trimethylolethane, trimethylolpropane, pentaerythritol or dipentaerythritol.

Typical oil and fat components include coconut oil, hydrogenated coconut oil, [Cardura El (glycidyl ester of persatic acid manufactured by Shell in the Netherlands), and octylic acid. Rice bran oil fatty acids, tall oil fatty acids, soybean oil, castor oil or dehydrated castor oil can also be used.

The alkyd resin of the present invention is prepared by either the melt method or the solvent method using the various raw materials listed above and according to known production methods.

The thus obtained resin of the present invention is particularly suitable for automobile solids and
It is used for color coatings and provides a coating film that not only has a high degree of weather resistance but also has excellent pigment dispersibility, waxing resistance, gloss, and curing properties.

Next, the present invention will be specifically explained with reference to Examples and Comparative Examples. In the following, all parts and percentages are based on weight unless otherwise specified.

Example 1 300 parts of coconut oil, 0.15 parts of lithium hydroxide and 132 parts of trimethylolpropane are added to a four-eye flask equipped with a stirrer, temperature i1, reflux condenser with dehydration trap and nitrogen gas introduction device. After carrying out an alcohol exchange reaction at 250°C for 1 hour, 77 parts of trimethylolpro9-pane and 20 parts of [Super Beckamine P-198J, 9
4 parts of pentaerythritol, 351 parts of hexahydrophthalic anhydride, 44 parts of phthalic anhydride, 49 parts of p-tert-butylbenzoic acid and 40 parts of xylene were added and kept at 160-180°C for 3 hours. to 180℃
The temperature was gradually increased over 2 hours from (hereinafter abbreviated as "1 jo degree") was V, an acid value of 7.2, and a hydroxyl value of 75. A solution of an alkyd resin was obtained.

Example 2 400 parts of coconut oil, 0.42 parts of lithium hydroxide and 123 parts of pentaerythritol were charged and heated at 230°C.
After a time alcohol exchange reaction, terephthalic acid was added to 275 parts of 1,1,3-cyclohexanedicarboxylic acid, 52 parts of benzoic acid, 95 parts of pentaerythritol, 25 parts of neopentyl glycol and 40 parts of xylene. The procedure was the same as in Example 1 except that a mixture of 5 parts of phosphorus pentoxide and
．． A solution of an alkyd resin having a hydroxyl value of 4 and a hydroxyl value of 66 was obtained.

Example 3 265 parts of "Cardura E", 297811 hexahydrophthalic anhydride-10-acid (7), 184 parts of isophthalic acid, 123 parts of pentaerythritol, 155 parts of neopentyl glycol, 52 parts of hexahydrobenzoic acid, [Using 30 parts of Agitol XL-180J and 40 parts of xylene, a dehydration condensation reaction was immediately started at 160 to 180°C for 3 hours, and thereafter the viscosity T-
A solution of an alkyd resin having U, an acid value of 4.8, and a hydroxyl value of 69 was obtained.

Example 4 142 parts of coconut oil fatty acid, 130 parts of isophthalic acid, 1
゜401 parts of 4-cyclohexanedicarboxylic acid, 194 parts of trimethylolpropane, 95 parts of neopentyl glycol, 168 parts of 1,6-hexanediol, 40 parts of xylene and [Superbeckamine P-198]
A solution of an alkyd resin having a viscosity M, an acid value of 6.0, and a hydroxyl value of 72 was obtained in the same manner as in Example 3 using 40 parts of J.

Comparative Example 1 The amounts of coconut oil and pentaerythritol were each 38
The amount was increased to 0 parts and 152 parts, and the reaction temperature was increased to 230°C.
After carrying out the alcohol exchange reaction in the same manner as in Example 1, except for changing to 40
A solution of an alkyd resin having a viscosity Z, an acid value of 73, and a hydroxyl value of 4.2 was obtained in the same manner as in Example 1, except that 40 parts of xylene were added.

Comparative Example 2 "Viscosity U, acid value 6.0 was prepared in the same manner as in Example 1 except that Super Beckamine P-1'184 was not used at all.
A solution of an alkyd resin having a hydroxyl value of 77 was obtained.

Comparative Example 3 After charging 320 parts of coconut oil, 221 parts of glycerin, and 0.15 parts of lithium hydroxide and carrying out an alcohol exchange reaction at 230°C for 1 hour, 29 parts of ethylene glycol and hexahydrophthalanhydride were added. except that 485 parts of acid and 40 parts of xylene were added.
Viscosity R-3. A solution of an alkyd resin having an acid value of 4.6 and a hydroxyl value of 66 was obtained.

Using the various alkyd resins obtained in the above Examples and Comparative Examples, each coating was made by coating $4.11 using the formulations shown in Table 1.
J/r-butyl □Cellosolve j/n-butanol = 40/30/20/10 (volume ratio) diluted with a mixed solvent in a 4-4 Ford cup for 23 seconds, and then air sprayed. 30-35
A test piece was prepared by coating to a film thickness of μm and then baking at 14 liters for 30 minutes.

Various coating film performance tests were conducted on each test piece.

The results are summarized in Table 2.1゜13- (2) Paint formulation for color fading test14- Test method and evaluation criteria Sharpness: Judging the surface condition of the paint film with the naked eye◎-- ---Excellent〇---Good Good Δ---Normal ×-Good
Displayed hardness: “Scratch” caused by “Mitsubishi Uni” pencil
is displayed with a minimum hardness that no longer occurs H+
-----H~2H F------HB-F Acid resistance: 5% H, 2SO4 aqueous solution on the coating film for 2~3 hours
Judging by the degree to which the coating film fades or shrinks after being dropped and left for a day and night◎----Excellent○--Good GoodΔ--Average ×-Fair XX--Poor Resistant to gasoline Quality: 16- Judgment ◎ --- Excellent 〇 --- Good 8 - Average × - Fair XX- - Weather resistance: In the case of accelerated weather resistance, the gloss retention rate (%) after 1000 hours and 1500 hours on the Sunshine Weatherometer, respectively, is displayed.On the other hand, in the case of outdoor exposure, the gloss retention rate (%) Gloss retention rate after exposure to city suburbs for 1 year and 2 years, respectively (
%) Discoloration due to wax: "Tenall" on flannel cloth (
Soaked in car wax (manufactured by Wilson, USA) and applied a load of 300
Pigment dispersibility: The red pigment and yellow pigment were respectively [Fastogen Super・Red BNJ! PCWIO%, and [Fastogen Yellow 4192J (17-benzimidacylon pigment manufactured by Dainippon Ink & Chemicals ■) at PWC15%,
Judgment is good based on the presence or absence of structural viscosity of the paint after kneading it in a sand mill for 1 hour.Good - 111 If there is no viscosity Poor - 1 - If there is viscosity Patent applicant Dainippon Ink & Chemicals Co., Ltd.18 −

Claims (1)

[Claims] The molar ratio of alicyclic carboxylic acid to aromatic carboxylic acid is 50
: 50 to 95:5, containing at least 30 vertical columns of the entire resin from which both of these carboxylic acids can be obtained, and 0.1 to 5 vertical columns of the entire resin from which an inorganic or organic phosphorus compound can be obtained. The oil length is 50% or less, and the number average molecular weight is